卤素取代改良热激活延迟荧光分子CzDBA性能的理论研究  

Theoretical study on improving the properties of thermally activated delayed fluorescence molecule CzDBA by halogen substitution

作　　者：林思榕 梁万珍 LIN Sirong;LIANG Wanzhen(State Key Laboratory of Physical Chemistry of Solid Surfaces,Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China)

机构地区：[1]厦门大学化学化工学院,固体表面物理化学国家重点实验室,福建省理论与计算化学重点实验室,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2022年第5期768-776,共9页Journal of Xiamen University：Natural Science

基　　金：国家自然科学基金(21833006,22173074)。

摘　　要：为获得更高性能的热激活延迟荧光(TADF)材料并认识其潜在机理,以具有良好荧光性能和高外量子效率的CzDBA分子为研究对象,通过卤素(F、Cl、Br)取代其受体单元上不同位点的H原子,设计了一系列新型TADF分子,并从理论上对其性能进行综合评估,计算了从最低三重激发态(T_(1)态)到最低单重激发态(S_(1)态)的逆向系间窜越速率(k_(RISC)).结果表明:Br取代能够显著加快分子的逆向系间窜越过程,其中受体单元上H原子分别被2个Br原子及4个Br原子取代的新型TADF分子的k_(RISC)均较原始的CzDBA分子提升了18倍以上.该工作为实验设计与合成TADF分子提供了可行的思路.In order to obtain higher performance thermally activated delayed fluorescence(TADF)materials and understand the underlying mechanism,the CzDBA molecule with good fluorescence properties and high external quantum efficiency is taken as the research object.A series of novel TADF molecules are designed with halogen(F,Cl,Br)substitution of hydrogen atoms at different sites on the acceptor unit of CzDBA.We then calculate their TADF properties and the reverse intersystem crossing(RISC)rates(k_(RISC))from the lowest triplet excited(T_(1))state to the lowest singlet excited(S_(1))state.It is found that bromine substitution can significantly accelerate the RISC process,and that k_(RISC) of our designed molecules,twoBr(with hydrogen atoms substituted by two bromine atoms on the acceptorunit)and fourBr(with hydrogen atom substituted by four bromine atoms on the acceptor unit),are above 18 times higher than that of the original CzDBA molecule.This work provides a feasible idea for the design and synthesis of novel TADF molecules in experiments.

关 键 词：热激活延迟荧光 逆向系间窜越 Marcus公式 卤素取代 

分 类 号：O644[理学—物理化学]